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Proceedings Paper

cSRM 2035: a rare-earth oxide glass for the wavelength calibration of near-infrared dispersive and Fourier transform spectrometers
Author(s): Steven J. Choquette; John C. Travis; David L. Duewer
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Paper Abstract

The National Institute of Standards and Technology is developing an optical filter standard for calibration of the wavelength axis of near infrared (NIR) transmission spectrometers. A design goal for the initial candidate Standard Reference Material (cSRM) filter was to provide absorbance peaks evenly covering the spectral region between 800 nm to 1600 mm (12,000 cm-1 to 6,500 cm-1). The reproducibility of the peak location, for batch-certified filters, was to be better than 0.02 nm (approximately 0.1 cm-1). Glasses with 1 to 3 mole % Yb2O3, Sm2O3, and Nd2O3, incorporated into a commercial lanthanum oxide glass were evaluated for this proposed optical standard. An initial batch of cSRM 2035 filters was prepared based on studies of glasses made and evaluated in our laboratory. An interlaboratory comparison study was initiated in February 1997 to evaluate the utility of these filters for the chemical, pharmaceutical, instrumentation, and regulatory communities. Information concerning peak-picking algorithms, wavelength coverage, geometry preferences, and other parameters was solicited from the users. Based upon input from the participants of this interlaboratory study, we are making several changes to make SRM 2035 more useful to our customers. Two of these changes are: (1) incorporating Ho2O3 into the glass to introduce an absorbance peak at approximately 2000 nm (approximately 5000 cm-1) and (2) providing users with a standard center of gravity (COG) peak-picking algorithm to locate the absorbance peaks of the SRM filter precisely. Recent results have demonstrated that the COG method provides a 10 fold improvement in the precision of locating peaks compared with traditional peak-picking methods.

Paper Details

Date Published: 8 October 1998
PDF: 9 pages
Proc. SPIE 3425, Optical Diagnostic Methods for Inorganic Transmissive Materials, (8 October 1998); doi: 10.1117/12.326655
Show Author Affiliations
Steven J. Choquette, National Institute of Standards and Technology (United States)
John C. Travis, National Institute of Standards and Technology (United States)
David L. Duewer, National Institute of Standards and Technology (United States)

Published in SPIE Proceedings Vol. 3425:
Optical Diagnostic Methods for Inorganic Transmissive Materials
Raju V. Datla; Leonard M. Hanssen, Editor(s)

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